Pharmaceutical chemists have worked over the years to provide more specific and potent drugs for the treatment of disease. In the case of cancer and other diseases which function by the creation of specific abnormalities of cells, most of the useful drugs have been of the cytotoxic type, which function by killing the abnormal cell. Such drugs are, of course, quite potent, and hazardous, even life-threatening, side effects are not uncommon. Thus, efforts have been made for some time to develop a mechanism for targeting such drugs directly to the cell to be affected, without administering a whole-body dose of the cytotoxic drug. Many patents and articles have been published on efforts to use antibodies for the targeting of such drugs. However, up to the present time, no antibody-drug conjugate has been approved for therapeutic use.
The present invention carries the science of drug targeting an additional major step forward, by providing controllable linker chemistry which allows the convenient attachment of multiple molecules of cytotoxic drug to a single molecule of antibody.